Understanding multimorbidity early in life takes a step forward
Authors: Mark A Ferro
Journal: The Lancet Public Health (2023)

Katriina Heikkilä and colleagues1Heikkilä K Metsälä J Pulakka A et al.Preterm birth and the risk of multimorbidity in adolescence: a multiregister-based cohort study.Lancet Public Health. 2023; 8: e680-e690Google Scholar used linked national registries from Finland and Norway to investigate the degree of prematurity and the development of multimorbidity (the co-occurrence of two or more health conditions, with none defined as the index condition) during adolescence. Using robust approaches to adjust for multiple testing and ignoring small effect sizes that were unlikely to be meaningful to public health or clinical practice, Heikkilä and colleagues' findings showed that earlier gestational age at birth was consistently associated with increasingly complex multimorbidity (ie, two, three, and four co-occurring conditions) in a dose–response manner. These novel findings represent an important step forward in understanding multimorbidity early in life, and offer tangible insights for addressing current knowledge gaps and improving the lives of individuals born premature. To date, the field of multimorbidity research has largely focused on adult populations;2van den Akker M Dieckelmann M Hussain MA et al.Children and adolescents are not small adults: toward a better understanding of multimorbidity in younger populations.J Clin Epidemiol. 2022; 149: 165-171Summary Full Text Full Text PDF PubMed Scopus (0) Google Scholar, 3Head A Fleming K Kypridemos C Pearson-Stuttard J O'Flaherty M Multimorbidity: the case for prevention.J Epidemiol Community Health. 2021; 75: 242-244PubMed Google Scholar however, this study by Heikkilä and colleagues, along with the few studies conducted previously,4Ferro MA Qureshi S Van Lieshout RJ et al.Prevalence and correlates of physical-mental multimorbidity in outpatient children from a pediatric hospital in Canada.Can J Psychiatry. 2022; 67: 626-637Crossref PubMed Scopus (5) Google Scholar, 5Silva DT Hagemann E Davis JA et al.Introducing the ORIGINS project: a community-based interventional birth cohort.Rev Environ Health. 2020; 35: 281-293Crossref PubMed Scopus (0) Google Scholar suggests that predictors and development of multimorbidity often occur early in life. Medical advances will indeed continue to help prevent premature births, allowing fetuses to develop in utero; however, more upstream public health and health system strategies that target the social determinants of preterm birth are warranted.6Hong X Bartell TR Wang X Gaining a deeper understanding of social determinants of preterm birth by integrating multi-omics data.Pediatr Res. 2021; 89: 336-343Crossref PubMed Scopus (6) Google Scholar As shown in Heikkilä and colleagues' data, the prevalence of preterm births is relatively high, and the health conditions identified represent those that are chronic in nature, which can result in substantial individual, family, system, and societal burdens of multimorbidity across the lifespan. Informing healthy public policy to address these burdens requires large-scale studies evaluating the extent to which multisectoral public health investments on key social determinants across health, education, and social services systems improve health and wellbeing and reduce costs. Examining the development of multimorbidity in adolescence is crucial; it is during adolescence that multimorbidity can compound the existing increased risk for poor mental and psychosocial health. Similarly, it is encouraging that Heikkilä and colleagues investigated the case of physical–mental multimorbidity (ie, at least one physical and one mental health condition). Research concentrating on physical–mental multimorbidity in young people is an emerging field of study that is still very much in its infancy; however, knowledge gains have been made by Tegethoff and colleagues in understanding the temporality of onset,7Tegethoff M Stalujanis E Belardi A Meinlschmidt G Chronology of onset of mental disorders and physical diseases in mental-physical comorbidity—a national representative survey of adolescents.PLoS One. 2016; 11e0165196Crossref PubMed Scopus (30) Google Scholar and by Arrondo and colleagues in quantifying condition-specific associations.8Arrondo G Solmi M Dragioti E et al.Associations between mental and physical conditions in children and adolescents: an umbrella review.Neurosci Biobehav Rev. 2022; 137104662Crossref PubMed Scopus (11) Google Scholar The study by Heikkilä and colleagues found that physical–mental multimorbidity had some of the strongest associations with preterm birth and similar dose–response effects across degree of prematurity, consistent with their overall analyses and with a previous report conducted by the investigators.9Heikkilä K Pulakka A Metsälä J et al.Preterm birth and the risk of chronic disease multimorbidity in adolescence and early adulthood: a population-based cohort study.PLoS One. 2021; 16e0261952Crossref Scopus (6) Google Scholar As physical and mental health care are often siloed within paediatric settings, leading families to navigate the health system on their own, these findings underscore the pressing need to prioritise coordinated care for individuals born premature, as well as a redoubling of efforts to seamlessly integrate physical and mental health care for children and adolescents. Indeed, previous evidence shows that young people with physical–mental multimorbidity have poorer psychosocial health compared with other morbidity groups—a finding that is in part a function of less-than-optimal health care provision for individuals with such complex multimorbidity.10Ferro MA Qureshi SA Shanahan L Otto C Ravens-Sieberer U Health-related quality of life in children with and without physical-mental multimorbidity.Qual Life Res. 2021; 30: 3449-3461Crossref PubMed Scopus (13) Google Scholar In addition to implementing integrated models of care to support timely and appropriate access to health care, system-wide studies of how integrated care is incorporated into transition planning for individuals born premature with physical–mental multimorbidity can provide the evidence needed to best support the complex care needs for these adolescents as they enter the adult health system. In their well designed study, Heikkilä and colleagues make efficient use of two national registers, reporting robust findings, which are appropriately tempered in the context of the limitations of their data sources, to infer that premature birth is an important characteristic that conditions risk for multimorbidity in adolescence. The investigators clearly articulate the need for mechanistic studies to explore the potential causal links between gestational age at birth and multimorbidity to advance this research agenda; a call that inherently requires a transdisciplinary approach with multiple stakeholders, including individuals and caregivers with lived experience. From a public health perspective, upstream strategies targeting social determinants of preterm birth and system shifts in the provision of health care are key opportunities to reduce the incidence of multimorbidity in individuals born premature and to improve health within the population. I declare no competing interests. Preterm birth and the risk of multimorbidity in adolescence: a multiregister-based cohort studyPreterm birth is associated with increased risks of diverse multimorbidity patterns at age 10–18 years. Adolescents with a preterm-born background could benefit from diagnostic vigilance directed at multimorbidity and a multidisciplinary approach to health care. Full-Text PDF Open Access